'Octomom' keeps watch over eggs for more than four years, MBARI scientists find

By Calvin Men, Santa Cruz Sentinel

Posted:
07/31/2014 08:49:05 AM PDT

Updated:
07/31/2014 09:45:15 AM PDT

MOSS LANDING - Forget about nine months. One octopus stood watch over her eggs for four and a half years before they hatched, according to researchers at the Monterey Bay Aquarium Research Institute.

The octopus, specifically the species Graneledone boreopacifica, set a record for the longest time any known animal has brooded over a clutch of eggs, according to a study published by researchers at the MBARI in Moss Landing.

"These surprising results emphasize the selective value of prolonged embryonic development in order to produce competitive hatchlings," researchers wrote in a study Wednesday published in the scientific journal "PLOS ONE." "They also extend the known boundaries of physiological adaptations for life in the deep sea."

The female octopus was first spotted in April 2007 in the deep waters off of Monterey. Researchers watched the octopus for four and a half years while she brooded over her eggs. (Monterey Bay Aquarium Research Institute -- Contributed)

In April 2007, researchers were exploring an underwater canyon off the coast of Moss Landing at depths of about 4,600 feet with a remotely operated vehicle for female Graneledone boreopacifica, a species of octopus known to lay eggs and watch over them in the area. While researchers found no brooding octopus, they noticed a lone female in the area.

A month later, they returned and discovered the same female -- distinguished by scars on its body -- in the same area brooding over a batch of eggs.

It was the first time the brooding period of a deep sea octopus had been documented from the beginning, said Bruce Robison, a deep sea ecologist at MBARI and lead author of the study.

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"Just to put things into perspective, the largest animal community on this planet are in the deep ocean," Robison said, adding that the underwater communities are important in the global ecosystem.

He added: "If we want to live on this planet in some kind of harmony with everything else that lives here, it's to our advantage to understand what goes on in the deep sea."

For about four and a half years, researchers returned to the site and octopus -- which they aptly named Octomom -- 18 times. Each time the tear-dropped shaped eggs grew larger, according to the paper. Yet researchers also noted the octopus, which was purple and highly textured, became more frail. Its skin color became was almost white, its eyes cloudy and its size diminished.

Despite small crabs and shrimp -- typical food for the octopus -- that swam and crawled near the female, she showed little interest in them other than to push them away from her eggs. The octopus, Robison said, likely never left the eggs for fear that predators would eat them and she likely ate little to no food during the more than four years of brooding.

This female octopus spent four and a half years brooding over her eggs on a ledge at depths of about 4,600 feet below sea level. The period is the longest period an animal was known to brood, researchers said. (Monterey Bay Aquarium Research Institute -- Contributed)

The octopus was last seen by researchers in September 2011 and a month after that, when they returned to the site, she was gone and the egg capsules were empty.

It was an emotional moment for everyone who became invested in the octopus -- the scientists, crew members of the ship and pilots of the underwater vehicle -- all of whom were impressed with the maternal instincts of the octopus.

"She died," Robison said. "No question about it. That's the rule of thumb for octopus and squid for that matter. They get one opportunity to reproduce which may be extended over a period of time."

While the octopus was absent, there were a number of young octopus in the surrounding rock.

Researchers deemed the brooding period at 53 months. By comparison, the longest uninterrupted period of brooding for birds is two months by the Emporer Penguin, according to researchers. The longest octopus brooding before this was 14 months by the species Bathypolypus arcticus in a laboratory setting. For animals that give birth to live offspring, elephants carry their young in the womb for 20 to 21 months and alpine salamanders can carry theirs for up to 48 months.

Researchers noted the long brooding period is an intersection of two factors: the low water temperatures at deeper depths and the advantage of producing highly developed offspring. The longer a mother is able to brood over her eggs, the more developed her young will become and the more advantage they'll have for survival, Robison said.

"We know so little about the deep sea that we're constantly being amazed by the things we learn," Robison said.